Category Archives: The female catkins are pollinated and develop cone-like structures which contain winged seeds that are released in late summer

Black Birch Catkins

November 29, 2025

The male catkins (or male flowers) of Black Birch (Betula lenta) form in the late summer and early autumn, overwintering in a dormant state. When spring arrives these catkins lengthen to 3/4 – 1 inch, and mature to release pollen to the wind. Black Birch is a monoecious tree, having both male and female catkins on the same tree.

Once the female catkins are pollinated they develop into cone-like structures, first green, turning brown in autumn. They contain small, winged seeds maturing during the warm months of summer and are released in late summer.

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